DE3925457C3 - Color image processing apparatus - Google Patents

Description

The invention relates to a color image processing apparatus according to the preamble of claim 1 and 5 respectively.

In a color image processing apparatus, e.g. B. one Color copier using a laser beam generator, become color image information by separating several Colors obtained from a color sample and color images recorded in accordance with the color image information.

In the color image recording, the device can by means of the built-in central processing unit (CPU) processing with variable magnification, partial color conversion processing and other types of image processing carry out.

The partial color conversion processing is as Image translation processing defined in which the Image information inside or outside of a designated Area with the area used to denote the area Color is recorded.

This color copier is characterized by the built-in Zen traleinheit determines whether the (Be driv-) condition of the components of the copier normal or not; depending on He The result of the copying operation is terminated or Signals for abnormal condition are displayed.

In this case, the state of the components by means of of the image signals estimated by a Image reading unit, e.g. a charge coupled or CCD Device to be read out when copying.

When done by the central unit checking the condition of the copier forming components, in particular the CCD device as image reading unit, or the examination of the (Verbin tion) separation of the e.g. in the form of a tungsten halogen Lamp present light source for original exposure the central unit can not be faultless or correct provide a decision. This represents a disadvantage of Estimation of the condition of the components of a copier räts dar.

When the light source circuit is turned off, the image signal level to zero. Based on the image signal can therefore be determined for sure if the Lichtquel le is disconnected or switched off or not.

The state of the CCD device as the image reading unit is but difficult to determine because namely their condition after a prescribed standard size is checked, however, the image signals, which the basis of the test, depending on the reading Geninhalt are different.

These image signals are different from the electrical ones Signals in which the exposed on a template or illuminated optical images are implemented. These signals can be image signals transmitted by AVR (automatic gain control) raised are, or be signals involving different types be executed by image processing.

It will create a color image sought processing device, which determines the state of the copy device components unique and easy to check or to can determine.

In a color copying machine of the specified type is a commercial tube lamp, e.g. a tungsten halogen or a fluorescent lamp, as a light source for Ausle used pictures. In the case of such a tube Lamp, the state of the light distribution must be checked who because in the case of poor light distribution the images of a template are not correct in color signals can be implemented.

When shipping copiers from the factory is the light distribution state usually by means of a Synchroscope tested. The light distribution is here limited to one point of light investigated, for example on the basis of converted data from the center of the light source.

In practice, it turns out to be difficult, a Synchroscope to the location of the user of the device bring and there the light distribution of the light source check.

When doing so in the course of maintenance or inspection At the place of use, a lens or a CCD device is replaced as an image reading unit, the Bestä the results of the light distribution setting not easy. Therefore, only the light distribution in Lichtquellenzentrum examined so that in this Wei se the light distribution in the total range not bestä be confirmed or confirmed.

From DE 34 08 108 A1 is an image processing device known in which a so-called Shading correction is made. Under one "Shading" is thereby an unevenness of the Picture light to be understood by various optical Factors such as the light source, the lens etc. is caused. When the shading correction is for one-line reading of a plain white plate Shade write / read memory provided. On Shadow correction memory gives read Correction output from the shading data which are stored in the random access memory are.

Furthermore, DE 31 01 552 A1 describes a method for Pre-processing an image signal before feeding in an operation circuit of a picture display device. at This method is a template photoelectric sampled so as to obtain image signals in the usual way. Stored in a memory characteristic Conversion data is then read by the image signal. This characteristic transformation data eventually becomes changed into other characteristic transformation data, wherein the desired reproducible density range of Template is taken into account. Image signals are so Compensable to the density range of the reproduced Image to the ultimately available density range adapt.

Furthermore, the US 38 93 166 deals with a Color correction method, which uses a memory Correction values are retrieved, which are a desired Relationship between an input signal and a Output signal mediated.

From US 46 79 073 is an adjustment system for a Color image reading apparatus known in which the strength of a a color template scanning light beam is adjustable. This is reflected by a reference template Light beam evaluated. Depending on this evaluation will the brightness of the light beam looking light source controlled.

Finally, DE 35 40 528 C2 describes a color Reading device, which different colored light sources used, each light a basic color on one Throw the original. A sensor receives in one Color balance phase before the actual exposure of the original individually the light reflected from a white background the successively controlled light sources. In a Color balance phase provides a control device  for each light source the light emission duration and the Integration period of the sensor such that the Peak value of the output signal of the sensor for each Light color is about equal to a predetermined reference value. A memory stores the time history of the thus obtained Output signal during integration for a subsequent color reading phase. In this known color Reading device so in particular the output signals averaged by B, G and R CCD sensors by the Accumulation time of the CCD sensors according to the Irradiation energy of the B, G and R light source changed becomes.

It is an object of the present invention to provide a To provide color image processing apparatus that it allowed to easily and usability or Verify operability of a scanning unit.

This object is achieved in a color image processing apparatus according to the preamble of claim 1 or 5 according to the invention by in its respective characterizing part contained features.

Advantageous developments of the invention will become apparent the dependent claims.

In an image processing, a on photoelectric Paths transmitted image signal into a digital signal converted, using different types of signal processing be performed in the form of the digital signal.

Therefore, usually by an image reading unit photoelectrically transmitted analog image signal by a Amplifier amplified to a suitable level and a A / D converter for sampling and quantization supplied. there the gain of the amplifier is controlled so that the A / D conversion output on a line, e.g. in the Center, which can take on the highest size.

A level adjustment, i. one before the A / D conversion occurring process, carried out by control or Control of an amplifier in such a way that the A / D conversion on a line, e.g. in the center, the highest Size achieved.

This is based on a general rule, namely that in Using a rectilinear light source for the photoelectric conversion the light distribution in the center or in the middle range is more intense than in the perimeter or Border area. In the case of a straight or linear Light source whose luminous intensity is greatest in the center, there is no problem.

However, some light sources show light distribution patterns, where the light intensity of or at the perimeter or Edge area is larger than in the center.

So far, it was assumed that the light intensity is always in Center of the light source is the largest. The level of the photoelectric conversion signal was determined according to the in the center of a line obtained photoelectric signal set. For this reason, runs in the above case the A / D conversion output is over Range exceeded, so that the photoelectric signal can not be properly A / D converted.

The invention thus also aims to provide a Color image processing apparatus in which a proper A / D conversion is feasible even if used a light source with concentrated light distribution and in which there is no overflow of the A / D conversion output signal occurs.

The erfindungsge Permitted device can according to the level of a Determine the number of digital color signals mentioned len, whether the operating state of a Bildausleseein is perfect or not.

In a first embodiment is based on the Level of digital input from the memory unit Color signals checked if the Condition of the components is satisfactory or not.

A digital color signal is as a signal de Finished by reading the from a white Stan dard plate or surface reflected from a light source of emitted light by means of a photoelectric converter unit, such as a CCD device, Won will become.

According to a second embodiment, he includes inventive color image processing apparatus a Unit for separating a color image information in a number of color separation images and for implementing the same in a number of color information, an on unit for obtaining digital color signals from this Number of color signals or information and one Storage unit for storing the digital signals.

The level is checked depending on the digi talen color signal, and the sampling position on one Line of the digital color signal used for the test is used, is adjustable. This is one of the Merk Male of the second embodiment.

In the second embodiment, the Lichtvertei tion of the light source as a function of the level of a Number supplied by said memory unit recorded digital color signals, and the results are shown. When capturing the light distribution is the sampling of equal to one-line digital color signals moderately performed to the entire light distribution of To determine the light source.

Due to this method, there are no Detektorvor directions, such as a synchroscope; the to stand the light distribution can be about almost all Be detected light source areas across.

A third embodiment of the Color image processing apparatus comprises a photoelek tric converter unit for conversion an image information in electrical signals and a Unit for winning digital color signals from the photoelectrically converted signals.

Here, the level setting of the photoelek trically converted signals as a function of color gnals that are of a maximum light density position a line were obtained.

In the third embodiment, the Position of maximum light density the light source in the direction of horizontal scanning de tektiert. The light distribution of the light source is determined on the basis of the detection result.

The color signal level is adjusted so that the the position of maximum density of the light source obtained Signal level can be used as standard level.

By this method, the A / D conversion process is carried out tion always performed with the highest efficiency.

Since the density level of the highest density position the light source obtained color signals to the standard level is set, shows the A / D conversion no overflow.

In the following, preferred embodiments of the Er invention explained in more detail with reference to the drawing. It demonstrate:  

Fig. 1 is a block diagram of a Farbbildverarbei processing device according to an embodiment of the invention,

Fig. 2 is a graphical representation of a Farbdiskriminierplans,

Fig. 3, a density histogram,

Fig. 4 is a schematic depicting lung of a change of colored markers,

Fig. 5 extract a schematic representation of a space,

Fig. 6 is a block diagram illustrating a central processor correlation,

Fig. 7 is a graph showing th Empfangsda,

Fig. 8 is a graphical representation of transmission data,

Fig. 9 is a diagram showing the relationship between A / Ausgangsprüfdaten and the transmission or transmission mode,

Fig. 10 is a graphical waveform diagram for illustrating the transmission mode,

Fig. 11 is a flowchart of an example of a processing operation in a Bildverarbei tung-central processing unit,

Fig. 12 is a flow chart of an example of the processing operation in the central processing unit for a scanner;

Fig. 13 is an illustration of an example of a light distribution indication,

Fig. 14 is a graph showing the relationship between a central pulse and Abtastpi xels,

Fig. 15 is an illustration of the relationship between test results of the light distribution and Übertra approval or transmit data,

16 is a flowchart showing an example of a processing operation in an image processing CPU and FIG

Fig. 17 is a block diagram of a processing device Farbbildverarbei approximate shape according to another exporting.

Fig. 1 shows in a block diagram a first Ausfüh tion form of a color image processing apparatus according to the invention. The image signal processing in this apparatus will be explained below.

A color image information or an optical image of a photographic object 2 , for example a document or an original, is separated by an optical system 3 on a dichroic mirror 4 into two color separation images. In this example, a color image is separated into a color separation image of red R and one of green and cyan Cy, respectively. For this reason, a dichroic mirror 4 of a cut-off wavelength between 540 nm and 600 nm is used.

The color separation images of red R and cyan Cy are projected on image reading units such as CCD devices 6 and 7 . The image signals of a red component R and a cyan component Cy are output from the respective image reading units.

The image signals R and Cy are supplied to A / D converters 10 and 11, respectively, and converted into digital signals of a prescribed number of bits, in the present case into digital signals of 6 bits. In the A / D conversion, a shading correction is performed at the same time. For this purpose, shading or Farbtonkorrek tion circuits 12 and 13 are provided.

After hue correction, digital image signals are screened out. The extract size is the signal component corresponding to the width of the largest original size, and the extracted signal component is fed to a downstream Farbdiskriminierschaltung 20 to. When the largest width of the original is in the format B4, the size or format signal B4 generated in a clock signal generator unit 170 is used as the gate control signal.

The hue correction subjected digital image signals are denoted by VR and VC. These image signals VR and VC are supplied to the color discriminating circuit 20 and separated into a number of color signals.

The present example relates to the case in which the image signals in three color signals, i. Red, Blue and black, to be separated.

In this case, the color signal becomes regardless of the color the template at each pixel one of the colors red, blue and black assigned. After performing this verar Processing will be any section or area of the template as a section of one of the colors red, blue and Black recognized.

The color discrimination processing may also be for others Colors are red, blue and black; as well For this more than four colors can be used.

After color discrimination processing, each one exists Color signal from the color code data (2-bit data), which represent the respective color information, and their Density information (6-bit data).

In a example, as read-only memory or ROM executed color discriminant conversion table (Plan) stored data are each as a color used.

Fig. 2 illustrates an example of the color discrimination conversion table.

It is possible to prepare various color-discriminating conversion tables and use one of these tables depending on the type of the original. In this case, the table selection is carried out as a function of commands by a microcomputer 160 for the processing of images which will be explained in more detail below.

The color-discriminated image data is the color image ver supplied processing.

First, image data is fed to a downstream color error correction unit 30 , whereby the color errors in the primary scanning direction (horizontal scanning direction) and the secondary scanning direction (drum rotation direction) are corrected.

Discriminating against color is unnecessary Color ghosts or color errors in particular black letters around. The color error or Farbgeisterbildkorrektion aims at the recovery single from color code data.

After the above correction, the density data in the color data (color code data and density data) are processed in a resolution MTF correction circuit 40 to correct its resolution.

The factors that affect the resolution are Pro in the optical system, in the optical drive system, in the Signal processing system and in the recording system. Of these systems, the optical system and the Optiktriebssystem a direct influence on the Resolution.

The resolution-corrected density data and the color code data are supplied to a color data selector 50 one by one. When the partial color conversion mode is selected, the image area is recorded after a certain color ( Fig. 4).

When executing this partial color conversion mode and other image processing it is necessary  Marker signals RP and BP from the drawn on the template Color mark to detect and the area or the Hide the surface.

For this purpose, a range extraction circuit 60 is provided. The color mark area on a page is detected, and the area information QR 'and QB' (see Fig. 5) from this circuit is supplied to the data selector 50 .

Besides these signals, a scanning code signal indicative of the color to be copied or copied and the partial color conversion signal CC are supplied to the data selector 50 .

The scanning code signal will be described later. In a multicolor copier, which in several be It is possible to copy the agreed colors with each order Rotation of a photoconductor drum one color image developed, taking after the development of all color images transfer these to a record carrier and be recorded with it. In this copier The sample code signal indicates the color instantaneously is being developed.

Therefore, if a blue color marker is detected, ar works the device in the blue copy operation. The Images in a blue color marker may be in blue be drawn by the color data according to the Signal are output when the area or Be signal is gained.

If the device is not in partial color conversion processing mode works, the density data will only be output when the color code data with the scan code a coincide. In other words, if that is Device is in the red-copy operation, wherein the Red color code is obtained, the corresponding Density data selectively output.

The image data output from the color data selector 50 , ie, density data, is enlarged or reduced in a scale adjusting circuit 70 .

The magnification and reduction or imaging scale processing is done by interpolating the Density data in the direction of the primary scanning and through Control of the scanning speed in the direction of Se scannings, i. the direction of rotation of the photo Head drum.

As the scan speed is increased, it will Image shrinks because the sample data in the direction of Secondary scanning "thinned". If, however, the Scanning speed is reduced, there is a Image processing in the sense of an enlargement.

In this embodiment, the color code data is also simultaneously enlarged or reduced, and then fed to a multi-digitizing circuit 80 .

The density data subjected to the enlargement or reduction processing is repeatedly digitized by the circuit 80 . For example, using four threshold values, the density data composed of 6-bit data is digitized five times. The threshold is set manually or automatically. In the described case of execution, a histogram specifying circuit 100 is provided for this purpose, in which a density histogram shown in Fig. 3 is screened out with the image data. Based on the density histogram, the optimal threshold for the image is calculated.

For each color, a density histogram is taken, so that the multiple digitizing processing on every color as determined on the basis of the histogram calculated thresholds can be performed.

The multi-digitized th data consisting of 3-bit data are fed via an interface 130 to an auxiliary computer 160 . The multiply digitized signal is fed via the auxiliary computer (CPU) 160 to a laser beam printer 150 which is part of the output unit. By this multiple digitized or multi-digit signal, the laser pulse is modulated in width. The laser beam generates a latent image on the photoconductor drum in the laser beam printer 150 . The laser beam printer 150 generally performs a reverse development.

All commands and the timing of the image processing are controlled by the auxiliary computer 160 .

The entire processing or processing time clock is generated by a processing timing signal generator 170 , including the signal at the time of commencement of reading by CCD devices CCD6 and CCD7. A timing generator circuit 180 serves to provide a timing clock for the training scale change.

In the embodiment of Fig. 1, on the basis of the Farbdiskriminierschaltung 20 fed digital color signal, that is, based on the digital color signal obtained when scanning the white Stan dard area, the state of the components of the copier is checked whether he is flawless or not.

For this reason, the digital color signal obtained from the prescribed area by a latch circuit 200 is latched and then supplied to the auxiliary computer or central processing unit (CPU) 160 for image processing.

The central color unit 160 fed digital color signal is further fed to a main or scanner Zen traleinheit 250 which controls the optical scanning system and the scanner. In this way, it is checked whether the density level of the digital color signal is correct or not and whether or not the state of components, particularly the CCD devices CCD6 and CCD7, is satisfactory.

Fig. 6 illustrates a relationship of Signalübertra movement between the image processing CPU 160, the scanner central unit 150 and a printer Zen traleinheit 150 A.

External synchronizing signals such as horizontal and Verti kal-effective area signals HV and VV, an index IDX indicating the starting point of each horizontal scanning and a clock signal CLK, from the printer Zentralein unit 150 A to the timing signal generator circuit 170 from optionally.

Index change signals IDX and EX are supplied to the generator circuit 170 from the scanner CPU 250 . These are control signals for switching over the inter-synchronizing signal generated in the generator circuit 170 and the aforementioned external synchronizing signal.

Apart from that, a signal COR, which determines the beginning time of the shading or Farbtondatenabta Stung, a reference signal REF and a Vorabtast signal PRE are fed. The reference signal REF is a control signal which changes the standard voltage of A / D wall learning 11 and 12 . The pre-scan signal PRE is a pre-scan control signal for taking a histogram before the original reading.

All these signals, such as index change signals IDX  and EX, signal COR for determining the start time of Sample, reference signal REF and pre-sample signal PRE, are active.

The row correspondence signals are exchanged between the image processing unit 160 and the scanner central unit 250 as follows: A request signal REQ is a signal for controlling the exchange of serial data between the scanner central unit 250 and the image processing CPU 160 . These units are synchronized with each other by a series clock signal SCK.

RxD designates data transmitted or transmitted by the scanner (received data). TxD stands for serial data (transmission data) transmitted from the image processing side. Actual examples of the transmission and reception data RxD and TxD are shown in FIGS . 7 and 8.

The receive data RxD consists of 7 bytes, and the low-order 3 bits in the first byte are CHKIP for input / output check data. The relationship between the check data CHKIP0 to CHKIP2 and the transmission mode or transmission mode selected therewith are shown in FIG .

In this embodiment, there is besides the mode I, i. normal reading mode, in which for the test the quality of parts of the device necessary digital Color signals are transmitted in the form of TxD, including the Fashions II and III. The data transferred in mode I are the digital color data for red and cyan.

The mode II is a transmission or transmission mode that then used when the image reading position (data ver locking position) is changed on a line to the light distribution status of the light source at almost all effective areas. Transmission data are as in mode I, digital red and cyan color signals le. The locking pulse used here is the Central impulse CPS.

Mode III adjusts the light distribution as in mode II. This mode is used to de detecting or detecting the position of maximum level the rod-shaped light source. In this mode will even if the central pulse CSP to change used the image read-out position.

Among the transmission data TxD shown in FIG. 8, C ₀ to C ₅ and R ₀ to R ₅ indicate the level of digital cyan and red signals consisting of 6 bits.

The following codes are each byte of the received data RxD assigned:

1. SC0-SC2 scan code 2. CHANG Partial color conversion code 3rd EE Automatic threshold selection code 4. CHKPRE Vorabtastcode 5. RD0-RD3 Red-density level 6. BL0-BL3 Blue-density level 7. BK0-BK3 Black-density level 8. HZ0-HZ3 Magnification degree for main scanning direction (50-400%)

The following signals are exchanged traleinheit between the sample-Zen 250 and the printer CPU 150 A of FIG. 6: A pulse START as one of the pulses supplied by the central processing unit 150 A indicates that the scanner starts scanning. Transmission or transmission data TxD1 are obtained or obtained when the magnification degree or imaging scale is specified. Thus, the Abtastgeschwindig speed in Sekundärabtastrichtung for the scanner is designated net or predetermined. All of these signals or the like are synchronized with each other by the series clock SCK1. The image data or reception data RxD1 to be actually copied are transmitted by the central processing unit 250 .

The sensor output signal indicating the scanner rest position is fed to the scanner central unit 250 by a sensor 350 . A light control circuit 360 is controlled by the scanner central unit 250 he witnessed light signal. By the light control circuit 360 is a light source 370 , for example, a halogen genlampe or the like driven. A driver circuit 380 is driven by a Motoransteuer- or Trei bersignal. In this embodiment, the state of components, in particular the CCD device and the light source 370 is checked when the optical system of the scanner is in the Ruhestel development.

Referring to Fig. 10, first, the light source 370 is activated by operating a copy start key (see Fig. 10B in Fig. 10). After lapse of a predetermined period of time, the pre-scan signal PRE becomes active and the scanner 250 starts the prescanning operation. Prior to the above-mentioned operation, the information is scanned on the white standard surface (see A and B in Fig. 10).

Subsequently, the sampling start signal COR becomes active (see D in Fig. 10). The image data for red and cyan are stored in the memory built in the hue correction circuits 12 and 13 . In performing the prescan, the reference voltage REF is switched to the data stored in the hue correction memories (see I in Fig. 10).

During prescanning, a histogram of the spe the area of the image α on the original provides.

When the prescanning is completed, the reception data RxD is transmitted to the image processing CPU 160 by means of the request signal REQ (see E and F in Fig. 10).

The received data RxD are evaluated by the CPU 160 . When the set mode is Mode I, in which it is checked whether or not the state of components of the apparatus such as CCDs 10 and 11 , light source, etc. are satisfactory, the obtained image data becomes for red and cyan to the scanner CPU 250 , inserted in the transmission data TxD.

The transmitted or transmitted data are evaluated in the Abta-central processing unit 250 , whereby the loading operating state of the respective CCD device is weighed tet.

If, in the test, the CCD device and other components have been found to be satisfactory, copying of the first document sheet occurs after completion of the prescanning mode (see Fig. 10). At this time, the index change signal IDX.EX is reversed (see H in Fig. 10) and synchronized with the signals (IDX HV, VV) to scan the images on the original and process the data. The image data in the vertical effective area signal VV are later processed (see J in Fig. 10).

Shading or hue correction is performed in accordance with the image data sampled from the reference signal REF (refer to I in Fig. 10).

FIG. 11 is a scanning diagram 400 for illustrating an example of a control program for evaluating the state of components stored in the image processing center unit 160 .

When it is determined that the request signal REQ has increased, the input of the reception data RxD starts. When the input of all data (7 bytes) is completed, the reception data RxD inputted with the first two are decoded (steps 401 to 404 ).

When it is determined as a result of the decoding that the present mode is not the transmission or transmission mode I, the processing routine transfers to another processing routine 405 . When the transmission mode I is present, the digital red and cyan signals latched by the central pulse CSP are input (step 406 ).

The clock is set so that the Central pulse CSP can be obtained when the middle area of a line or line is dismissed is steady.

The input data is supplied to the scanner CPU 250 as transmission data TxD. If the transmission data is 2 bytes, the transmission mode is ended and the data goes through this processing routine (steps 407 , 408 ).

In dependence on the transmission data TxD, the Abta-central unit performs the decision or Prüfverar processing 420 of FIG. 12.

First, the transmission or transmission data TxD is input. Then, the data is checked to see if they are 2 bytes or not (steps 421 , 422 ). When transmission data of 2 bytes is input, the density levels for red and cyan are compared from these data with standard density levels (steps 423 , 424 ).

All standard density levels are on the center of the maximum density level set. If the maximum you level is 63, the default level should be at about 31 be set.

If all density levels are above the standard level, the CCD device and the light source are assumed to be matte free, and the process moves to the next copy (step 425 ). If one of the density levels is below the standard levels, it is decided that the CCD device is disturbed or the setting is wrong, whereupon the processing for executing corrective actions is performed (step 426 ). As a result, a copying process is prevented, or it will be provided by lighting eg as a warning lamp, a warning for the presence of a disorder delivered.

If the red and cyan density levels are both below the standard levels, it is decided that the light source must be replaced because its intensity or light intensity has decreased or the light source has failed. The relevant fault is displayed on a display. This test and processing takes place in step 426 .

In the described embodiment, the state of the components based on the density level of several of Farbdiskriminiereinheit fed digital Farbsi checked.

The plurality of digital color signals are de Finished by measuring the reflected light with a photoelectric conversion unit, such as a CCD device and the like; in front of lying case is the reflected light around that emitted from the light source, from the white one Standard surface reflected light. Then the Analog signals converted into digital signals, the Output signal after the A / D conversion is obtained. This embodiment of the invention therefore has the following features: The operating condition of the CCD device, insufficient light intensity of the Light source and a failure or failure of Lichtquel le can be easily and clearly determined.

In the second embodiment of the invention, the Light distribution of the light source based on the digital Color signals checked, which then received if a default template, in the present case the white standard area is scanned.

The obtained from the prescribed area digita len color signals are locked by the latch circuit 200 and the image processing Zen traleinheit 160 fed. The central pulse CSP is used as a locking pulse and will be explained in more detail later.

The digital color signals fed to the central unit 160 are further fed to the central unit (main central unit) 250 which controls the optical system (scanner), the light distribution being shown at.

A request signal REQ used in the light distribution confirming mode is a signal for controlling transmission and reception of serial data between the scanner central unit 250 and the image processing center unit 160 . This signal is or is synchronized by the row clock SCK.

When in the second embodiment, the device in the Setting mode is in which maintenance or lnspek At the same time, the To stood the light distribution tested.

In the light distribution setting mode (see E, F and G in Fig. 10), the information is scanned on the white standard surface when the light source 370 is turned on and the optical system of the Abta sters is in the rest position.

The received data RxD be gene according to the instruc commands or the request signal REQ to the image processing CPU transmitted (see FIG. E and F in Fig. 10) the 160th In the CPU 160 , decision processing is performed at each scanning position corresponding to the reception data RxD. The check causes 2-byte data to become the transmit or transmit data TxD. The test is carried out for each color signal.

The decision or test results are transmitted together with the transmission data TxD for each color signal to the Abta central processing unit 250 , and the results are displayed (see G in Fig. 10).

The display is made at each scanning position for each color signal (see Fig. 13). As a display element, a light-emitting element can be used; the display can take place as follows: When the signal level is low, the LED element is turned off. When the level is normal, the light-emitting element is turned on. When the level exceeds the standard value, the LED element is alternately turned on and off.

In the light distribution confirmation mode, the signal obtained by scanning a line of the LED element is converted into a digital signal, and the density level of the signal is evaluated for each color. In this second embodiment, a plurality of scanning positions are given in the direction of the light source so that the density level for each color can be confirmed over virtually the entire area of the light source, ie, detected. It is assumed that the effective area of a line or line portion of the light-emitting element in the direction of the light source is divided into seven units, are screened from each sub-area data and the effec tive surface consists of 5000 bits. In this case, the position of the pixel to be locked, ie, the scanning position, is shifted by linearly changing the central pulse CSP (CSP1-CSP7) in the order of FIG .

If the first sample position is the 480th pixel of the CCD device is the second position corresponds to the 1152. pixels and the last position the 4592th pixel.

The light distribution adjustment mode is represented as Mode II placed, which consists of two channels. First and two Each channel includes the light distribution confirmation cyan or red.

The data PxA and PxB among the transmission data TxD of FIG. 8 are 2-byte transmission data showing the results of the density level check in the light distribution adjustment confirmation mode I.

In the present case, x denotes the sampling position in Direction of horizontal scanning, wherein in the present Case seven positions available. The same bit in the same sampling position shows the test results in this position.

The relationship between the state of the level check, the results of the level check, and the transmission data PxA and PxB representing the test results is illustrated in FIG . If, for example, the test result at or in the Abtastposi tion x is normal, the transmission data TxD are composed by coding, eg PxA = 1 and PxB = 0.

Fig. 16 is a flowchart for illustrating an example of a control program for confirming the light distribution setting.

When it is detected that the request signal REQ is present, the input of the reception data RxD starts. When all the data (7 bytes) have been input, the reception data RxD included in the first byte are decoded (steps 401 to 404 ).

If, after the decoding, the present mode is not determined to be the transmission or transmission mode II, the data processing transfers to another processing routine 405 . If the mode of operation concerned is the transmission mode II, the central pulse CPS1 of the central processing unit is fed (step 406 ). Then, the color signals designated by the test data CHKIP0 to CHKIP2 are checked (step 407 ). Since cyan occurs first, the cyan-related digital color signal is input first. Thereafter, the scanning position of the central pulse CSP are changed and the same data processing is carried out. After completion of the data input for all sampling positions, the decision is made or examination of the input level (steps 408 to 410 ). The number of these test steps corresponds to the number of samples (step 411 ).

When all the check processing is completed, the decision or check results are coded and the coded data is transmitted as transmit data TxD (step 412 ). When these transmission data reaches TxD 2 bytes, the transmission or transmission mode is ended.

The same processing is performed on the digital red color signal (step 420 ).

The above-described second embodiment of Invention is characterized by the following: In setting mode, the test or evaluation of the Density level according to the immediately before the color discrimination obtained digital color signal, wherein the scanning position on a line of the for the Bewer processing or testing used digital color signal is adjustable.

The light distribution of the light source le can without using an oscilloscope or other Devices are detected. Because the light distribution is almost along an entire line or line may, a deterioration state of the light source be determined exactly what a practical Vor part means. An operator can therefore, using the data, decide exactly if a Ju tion of the light distribution is necessary or not.

Next, a third embodiment of the present invention will be described with reference to FIG. 17, in which a color image processing apparatus according to the invention is applied to the above-described color copying machine. In Fig. 17, the parts and elements of Fig. 1 correspond de parts or elements with the same reference numerals as previously designated and therefore not further explained in detail.

The difference between Fig. 1 and Fig. 17 is that, as shown in Fig. 17, level adjusting circuits 8 and 9 are provided. In the latter, image signals R and Cy are set. The goal of density level adjustment is to avoid overflow in A / D conversion and to improve conversion performance. A density level adjustment is carried out so that the level of image signals, which herrüh ren of the Po sition maximum luminance of the light source, the standard level. The details will be explained later.

After the density level adjustment, the image signal is supplied to A / D converters 10 and 11 and converted into a prescribed number of bits, that is, in the present example, a 6-bit digital signal.

In this embodiment, in accordance with the Farbdiskriminierschaltung 20 fed digita len color signal, ie the obtained by reading or scanning the white standard area digital Farbsi gnals, the signal input to the A / D converters 10 and 11 input signal level set in advance.

At this time, the digital color signal obtained from the prescribed area is latched in the latch circuit 200 and supplied to the image processing CPU 60 . The central pulse to be described CSP is used as a locking pulse.

The central unit (CPU) 160 fed digital color signal is further fed to a central processing unit (main CPU) 250 which controls the optical probe system (Abtaster), and the level of the level adjusting circuits 8 and 9 in accordance with the signal level according to the determined Scanning position on or adjusted. At the same time, the maximum position of the light source is displayed.

In this embodiment, the level adjusting circuits 8 and 9 are set when the apparatus is in the maintenance and inspection mode. In this setting mode, an evaluation is made in the same manner as in the second embodiment.

The results of the evaluation or test are fed to the scanner central unit 250 for each color signal which will transmit as transmission or transmission data TxD (see G in Fig. 10). The level adjusting circuits 8 and 9 are driven by this data transfer so that the peak coincides with the standard level (the sampling level close to the maximum value). The peak position of the light source is displayed ( Fig. 13).

Multiple sample positions are processed in the same way as vorge in the second embodiment ben.

The level adjustment mode is shown as mode III, which consists of two channels, of which the first channel the level adjustment mode for cyan and the next channel the level adjustment mode is red.

The pixel position at the peak is e.g. as 1.1 defi ned. The pixel positions at a lower level as this peak, all are 0.0.

The peak detection control program is executed in the same manner as the light distribution setting confirmation control program of FIG. 16.

When it is determined in the pre-scan mode that the request signal REQ becomes active, the input of the reception data RxD starts. When all input data (7 bytes) are input, the received data RxD input in the first byte is decoded (steps 401 to 404 ).

If the decoding results indicate that the present mode is not the transmit or transmit mode III, the device will transition to another processing routine 405 . If this mode is the transmission mode III, the central pulse CSP1 is input to the CPU (step 406 ). The designated color signal is discriminated by the check data CHKIP0 to CHKIP2 (step 407 ). Since cyan is present first, the cyan-related digital color signal is input first. Subsequently, the scanning position of the central pulse CSP are changed and the same processing is carried out (step 408 ).

By means of the level adjusting circuits 8 and 9 , the apparatus is controlled so that the output signal at the sampling position where the peak occurs becomes the standard level. Due to this control, the peak value in a scan line is lower than the standard level. As a result, no overflow occurs in the A / D conversion.

According to the third embodiment, the lights distribution of the light source detected (or measured) and the level based on the output level of the Ab touch position where the peak value is determined provides.

Due to this setting, the peak becomes low ger as the default, so that's the problem can be solved that image signals due to a Overflow during A / D conversion not wall-free to be subjected to A / D conversion can. Even if the light distribution is more on the peripheral or peripheral areas as on the central Rich is concentrated, the accuracy of the A / D order be improved.

From the above description it is apparent that the Invention advantageous to a Farbbildvorvorvor direction, as the mentioned color copying machine applicable is.

Claims (4)

1. color image processing apparatus for scanning a color image, with

• an exposure unit ( 3 ) for illuminating an image ( 2 ) of standard density with light,
• - A plurality of photoelectric converters ( 6, 7 ) for converting the reflected light from the illuminated image into electrical image signals and
• a plurality of transducers ( 10, 11 ) each associated with one of said transducers ( 6, 7 ) and for converting the electrical image signals into digital image signals,
  characterized in that
• - a determination unit ( 20 ) determines the operability of a sampling unit by comparing each of the digital image signals with a predetermined reference level, wherein:
  • if the determination unit ( 20 ) determines that all digital image signals are below the reference level, the determination unit ( 20 ) decides that a light source of the exposure unit ( 3 ) has failed, and
  • if the determining unit ( 20 ) determines that at least one of the digital image signals, but not all the digital image signals are below the reference level, the determining unit ( 20 ) decides that there is a fault of the photoelectric converter.

2. Apparatus according to claim 1, characterized in that the scanning unit comprises at least one unit of the lighting unit and one of the photoelectric converter ( 6, 7 ). 3. Device according to claim 1 or 2, characterized by a display unit for displaying the determination results of the determination unit ( 20 ). 4. Device according to one of claims 1 to 3, characterized in that it is provided for a copying machine and terminates the copying operation of the copying machine when the determining unit ( 20 ) determines the scanning unit as unusable or not operable.